Low temperature liquid pump



aept. 15, 1936. J. oKADA LOW TEMPERATURE LIQUID PUMP Filed Dec. 18,. 1934 Patented seiia- 15, i936 UNITED STATES PATENT OFFICE I I TEMPE'SIGIJQUID PUMP n Jiro Okada, Sugami-ku, Tokyo, Japan yApplication December 18, 1934, Serial No. 758,084

In, Japan May I, 1934 2 Claims. (Cl. y10B-203) This invention relates to a low temperature liquid pump for pumping liquid which is easily vaporized at an' atmospheric temperature, characterized in that, a pump body is hung in a low temperature liquid container to submerge the whole body in the liquid so that the body is always maintained at the same temperature with the liquid, said body having an opening at about of the suction stroke of the piston to let out vapour generated and liquid in said stroke from the opening, thus forcing out liquid only at the delivery stroke, and the invention has for its object to obtain a low temperature liquid pump having the most high eiliciency for delivering easily vaporized liquid at an atmospheric temperature.

An annexed drawing is a sectional elevation of a low temperature liquid pump according to the invention, showing the pump body and an arrangement of the pump.

In the invention the whole body of a pump for forcing out liquid easily vaporized atan atmospheric temperature is hung in the low temperature liquid in a vacuum container and is main-- tained always at the same temperature with the tain quantity of liquid is discharged at the be-` ginning of the delivery stroke from the opening,

and after said opening is cut oil by the piston,

the liquid only is perfectly forced out thus the maximum delivery emciency of the pump being obtained, and constant and exact quantity of,

liquid being delivered per stroke.

When a liquidy easily vaporized at an atmospheric temperature meets with a substance of room temperature, there occurs a violent vaporization, and in a pump of an ordinary type having the body exposed to the room temperature, the' liquid is yaporized at once at the entrance of the suction valve and the pump cannot lsuck in the .liquidi but only vapour at the suction stroke of the piston. And if the liquid might be brought in the suction valve the liquid is vaporized in the interior of the pump body withoutdischarging any liquid from thedelivery valve. In the` present apparatus, however, the

whole pump body isv submerged in the liquid and is maintained at the same temperature with theA liquid, and .the suction valve is openedv mechanically, for example through lever and rod -mechanism actuated by cam on the crank shaft, 5 to suck in freely the surrounding liquid to the pump body-due to-its head, thus isolating said -body from the room temperatureto avoid any vaporization.

But as the4 other end of the piston rodftted to thepiston is exposed to the room temperature,

the surface of the piston absorbs very slightly an external heat through heat transmission, so that a minute quantity of liquid is vaporized lowering the suction efficiency.

In order to prevent this phenomena, any opening as in internalcombustion engine of-two cycle is formed extending from .about v80% of the suction stroke to the end thereof (as shown in the drawing) so that, Iat the upper stroke of the piston, the opening. is opened .and the body will make an intercourse freely with the surrounding low temperature liquid through the opening, and the vapour ilows out of said opening-without retaining any vapour in the body.

'Ihe reason for providing the opening extending from about 80% of the suction stroke to the end thereof will be understood in a reciprocating pump of a" denite crank radius, that' an ample time necessary to let out the vapour in the pump body from said opening can be obtained at that portion of the stroke, and also at the beginning of the delivery stroke, a certain quantity of the low temperature liquid is fully discharged from said opening and: after 35 the opening is cut oil? by the piston, the liquid only is forced' out to obtain the maximum eiliciency compared with apparatus with pump of former type.

The low temperature liquid containersubmerg- '40 ing the pump body therein consists of vacuum double walls for heat insulation as shown in the drawing with the outer wall covered with an insulating material, and cold vapour generated naturally from liquid in the container is led to the 5 space between the container and an outer casing, said space being also arranged with coil of the deliverypipe to insulate the container from external heat. Y

In the annexed drawing, (I) is the body of a pump according to the invention, having the piston (2) and the piston rod (3). In order to submerge a pump body in a low temperature liquid container (4), the body is hung by rods (6)- Which are fitted to a frame (5), said rods hav- 55 heat transmitted from said frame due to heat conductivity, or the rods may be substituted by chains for the same purpose. Now, a certain quantity of a low temperature liquid (1) is lled in the container (4) and after the body is cooled down to the same temperature with said liquid.

`the suction valve (9) is opened mechanically by operating a lever (8) through a valve mechanism,

and theliquid (1) enters into the pump body from the suction port (IG) due to its `head so that the body will be full of the liquid by displaceautomatically by the suction stroke of the pis' ton to suck in the liquid (1). When the piston (2) reaches the openings (Il) extending 'from about 80% of the suction stroke to the end thereof, vapour, generated on account of heat trans-- mitted from an external atmospherethough the piston rods (3), flows out of the openings. to the surrounding liquid, and the interior of the pump body will freelymake an j intercourse'with saidV liquid without allowing the existence of any -vapour in the body.

Ai the beginning of the delivery stroke of the piston, ya certain quantity ot. liquid in the' body flows out of said openings (il) and after the piston cuts off the openings the liquid only is discharged from the delivery valve- (l2) to a.

pipe (I3) which is wound inthe space (I5) b 'etween the container (4) and heat insulating wall (Il) of outer casing, thus cooling the space, and l is led toA required-position And cold vapour generated naturally from the surface of the liquid (l) of the container (4) throughan opening-(I1) overflows down in said space' (l5), Dro-- tecting the space from entry of the external heat),

and then itis discharged from a port (I6). A'

, be operated'for high temperature'liquid 'with similar eil'ect. C. g

I claim: l. A low temperature liquid pump comprising -in combination-an engine supporting-frame, the

lower part of which forms av casing, aninsulated vacuum Acontainer supported within lsaid casing and -illei with a low-temperature liquid, ment of the piston. 'I'he valve (9) may be opened a lpump body including a hollow cylinder open at lits upper en d, a piston operating therein, said4 and rods attached at their upper ends to the plate and 'at their -lower endsl to the pumpV body. said rods being of such vlength that the pump bodyls completely submerged in the low tem- .perature liquid contained within the vacuum contailler.

2. A low temperature liquid pump as claimed' in claim 1, wherein the insulated container includes an air tight outer casing, an inner doub1e.

walled casing having an operi topso as to be lled with liquid and the outlet pipe being coiled around the outer surface oi the inner casing 'tol y facilitate cooling of the liquid contained in the inner casing. l Jmo gomma.y 

